The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present technology.
Once immersed in an aquatic environments, most objects become suitable substrates for the growth of biofilms and/or barnacles. Ships, for example, need to be protected from the growth of biofilms and/or barnacles by the use of antifouling coatings. Antifouling coatings on hulls serve multiple functions, for example, by protecting the hull from the corrosive effects of salt water, preventing life from growing on the hull, and (if pigmented) imparting color to the hull.
Antifouling coatings can reduce energy costs for ships. Hulls are designed to move through water with the least amount of resistance, and burn the least amount of fuel, while maximizing the carrying capacity of the ship. Hull design has advanced considerably over the last century. However, advancements in hull design can be at least partially negated by biofilm and/or barnacle growth on the hull. For example, biofilms can increase drag about 20 percent and barnacles can increase drag about 60 percent. The increased drag on a ship's hull, caused by bioaccumulation, increases fuel consumption. Further, the ship must be periodically taken into a dry dock where the hull can be cleaned at considerable expense. Existing antifouling coatings generally include metals such as tin (e.g., tri-n-butyl tin), copper, or arsenic. While effective, these metal-based antifouling coatings are toxic and damaging to the environment. Improved antifouling coatings are needed that inhibit the growth of biofilms and/or barnacles without substantially harming the environment.